What Happens To Our Body During A Flight?

body during a flight

Feeling of clogged ears, heavy legs and headaches: Passengers often report about these feelings during and after a flight.

This article will give you an idea of what actually happens to our body during a flight.


Flying, for many people, is as natural as taking the car, bus or train – but some facts about flying aren’t that obvious to everybody: Flying equals stress for the human body! What actually happens to our body at 30,000 feet? In short, flying is hard work for our organism, especially takeoffs and landings.


What happens to our body during a flight?

During takeoff, air pressure decreases rapidly inside the cabin. For a brief time, air pressure in the cavities of the middle ear and frontal sinus, in comparison to the air pressure in the cabin, changes. The eustachian tube is working full time to compensate for the pressure differences between the nose, ears and the environment. Takeoffs are less problematic; the emerging vacuum in the cabin causes an overpressure in the middle ear, but that is relatively easy compensated for by our bodies. More problematic are the landings, as air pressure increases gradually and causes a, sometimes painful, vacuum in the middle ear and leads to the eardrum to be vaulted inwards. Passengers often report having a feeling of clogged ears. Physicians suggest using nasal sprays, chewing gum or to yawn and swallow often for pressure compensation. Another method to induce pressure compensation is the Valsalva Maneuver; exhaling with a closed mouth and nose to open the eustachian tube.

Headaches are also often associated with the pressure gradient on board, as well as with the high noise levels during the flight. Ears are constantly exposed to volumes of 95 to 105 decibel. Any constant noise level at 85 decibel or more can lead to permanent hearing loss. Flying may also be mentally stressful. Cracking sounds or in-flight turbulence can cause panicking, simply because we, as in the passengers, are more or less helpless during an emergency situation. But more often than not, there are no rational reasons for these fears. Actual emergency landings are extremely rare, but the feeling of helplessness is enough to trigger anxiety in the human body.

Air pressure decreases vastly at 39,000 feet (typical flight altitude, with longer flights even higher than that) and humans are not able to breathe under these conditions. Pressure inside the cabin is therefore regulated to simulate an altitude of just 7,000 feet. This air pressure leads to a lower oxygen concentration. To efficiently utilize the limited oxygen supply, the body reacts by constricting blood vessels, raising the heartbeat, increasing blood pressure and breathing frequency. In 2016, Star Wars legend Carrie Fisher suffered a heart attack during a United Airlines flight from LHR to LAX, passing away 4 days later at the Ronald Reagan UCLA Medical Center in Los Angeles, CA. While there may have been additional factors involved, incidents such as these serve a reminder of how flights negatively affect the cardiovascular system. The risks for hypertension, cardiac arrhythmia and other coronary diseases increase due to the oxygen deprivation. The blood oxygen decreases, often leading to feelings of dizziness, fatigue and headaches.

Another drawback of lower air pressure is the expansion of gases, which causes unpleasant bloating and flatulence. It may also lead to congestion and other digestive problems, even days after the flight. The feeling of tension is often accompanied with a higher production of urine. It is therefore advised to go to the restroom often, as the short walks to the lavatory also help with blood circulation. Whether on a bus, train or plane, siting for several hours with bended knees can lead to poor blood circulation in the legs and a higher risk of blood clot development, which may lead to a life-threatening thrombosis. Sitting for an extended period of time can also give you a numb buttocks. Remedies to this can be short walks during the commute, compression stockings or certain exercises to help promote healthy blood circulation. This is particularly important as airlines, especially legacy carriers, continuously find more ways to further restrict legroom in economy class.

The body loses around 1.5 liters of water during a 3-hour flight due to dry air, with a humidity level of just 15 percent. This effect is especially noticeable in the nose, mouth and eyes, as the mucosa gets dehydrated. Combined with our tendency to catch up on sleep during flights and you have the perfect recipe for dehydration. It is therefore very important to remain properly hydrated during the entirety of the flight and avoid alcoholic and caffeinated beverages before, during and shortly after the trip. Moisturizers and eye drops may also be helpful. Fun fact: Ever wondered why tomato juice is so popular during flight? Because of the altered perception of taste due to the low air pressure on board, which is making us crave sodium.

body during a flight

Long flights also weaken the immune system due to several factors. In fact, catching a cold or flu is 100 times more likely during a flight. Major reasons are the air pressure and dry air that cause non-optimal conditions for the mucosa. Traveling is often tiring and the adrenal glands release stress hormones, which depress the immune system. The often chilling temperatures inside the cabin lead to a constant effort by our body to keep its optimal temperature. To keep the cold away, it helps to wear some warm socks, a scarf and to drink warm beverages. Also make sure to thoroughly and regularly wash your hands, use hand sanitizer and keep your hands away from your face. I personally like to use a wet wipe to clean my tray table and arm rests, as those have been reported to harbor more germs than the lavatory.

Two relatively unknown facts while flying are the cosmic radiation and toxic oil vapors. While flying, you are exposed to cosmic radiation. During a 7-hour flight, you are exposed to the same dose of radiation as during an x-ray procedure at your local clinic. Another, often withheld, risk is the pollution of cabin air with toxic oil vapors. Airplane engines are lubricated with oils that contain the toxic substance TCP (tricresylphosphate). TCP is a neurotoxin and very harmful to humans. Cabin air is often extracted from the engines and filtered through a seal. Nevertheless, those seals allow to pass TCP in small amounts, which are transported through the air condition system on board and then inhaled by the passengers. Symptoms may range from nausea, temporary lack of concentration and dizziness. However, the risk for occasional flyers are low since oil vapors are circulating in a very low concentration. But this may be different for the flight crew and frequent flyers.


How to decrease risks

  • Have a good and long night sleep before a flight
  • Keep your body well hydrated and eat light on the day of the flight
  • If you have health issues, consult your physician
  • Avoid alcohol, coffee and beverages with gas. Drink a lot of water or juices to stay hydrated. Carbonated drinks will only add to bloating and flatulence.
  • To minimize the risk of thrombosis, avoid constrictive clothing and have short walks every now and then. Do some stretching and exercises (Plane Yoga). If you have a high risk of developing a thrombosis, consider taking medication and wearing compression stockings.
  • Wash your hands often, avoid touching your face, use hand sanitizer and consider wearing a face mask (especially as a courtesy to other travelers if you suffer from a cold or flu yourself) to combat germs.
  • Use nasal sprays, chew gum or yawn and swallow often to help your ears compensate for the pressure difference.
  • Use ear plugs or noise-canceling headphones to protect your hearing.
  • Use saline and eye drops to keep your mucosa hydrated.


Bottom Line

Many of us find flying very enjoyable. Rightfully so, we’re doing something only a very few other species on Earth are able to do! But the anatomy of a bird is different from that of ours and their bodies have had millions of years to adapt to the stresses of flight. Aviation to us is just over a hundred years old and even experienced flyers are not immune to the negative physiological and psychological effects of being that high up in the air for that long of a time. Consider this: You spend hours inside a pressurized tube, filled with people from all walks of life, many of whom can carry germs their body may be tolerant to, but not yours, and are over 30,000 feet closer to the sun’s harmful radiation. There is a reason flight attendants carry an arsenal of flu medication and antibiotics, as well as being issued – at least by many European airlines – dosimeters to record their level of radiation exposure.

Please continue enjoying your travels – I know I will – but prepare your bodies with a healthy dose of sleep (which will also combat the usual post-flight jet lag), proper hydration and a little in-flight exercise. If need be, consider upgrading your seat to Premium Economy or Economy Plus for extra legroom to prevent at least some of these conditions.

What is your pre-, during- and post-flight ritual to remain healthy when traveling?